2. digital
  3. 1410013023

USB printer cable VS USB audiophile grade cable?

I have converted to PC audio about 2 years ago and enjoying the hobby. I recently upgraded my DAC from a Benchmark DAC1 HDR to a DAC2 HGC mainly to download DSD files. I am now using a 'regular' 12 ft. Belden USB printer cable purchased at Office Depot which sounds great. The Benchmark uses asynchronous clocking system to re-clock incoming bytes from the PC.

I just purchased an audiophile grade USB cable (Furutech GT2 Pro-USB). To my great surprise, this Furutech cable just trounced the printer cable. Noise level is down, music micro-details are popping up and bass goes down much lower. I've listened to some of my older CD's which I am pretty familiar with and hearing details I never heard previously. So it has nothing to do with jitter, since the Benchmark is handling it. The 'bits are bits' theory, which I subscribed to has some cracks to it...

Before I purchased this cable, I was of the opinion that the only sonical gain I would get would be better immunity to EMI/RFI since the Furutech has greater isolation. However, this purchase turned out to be of much greater sonical value for about $300.

I am perplexed and very happy at the same time :-)

What is going on?
128x128dasign

Showing 2 responses by audioengr

audioengr
3,282 posts
 
Better USB cables seem to have several attributes:

1 better shielding
2 heavier ground and power wires
3 better dielectrics
4 smaller signal wires
5 good impedance match

USB uses a differential signalling technique.. This inherently implies some common-mode noise rejection at the receiver. The problem is that these receivers dont reject CM noise vey well.

Some async USB interfaces use the power in the cable to generate the timing/clocking and therefore, any variation in this voltage can cause jitter. The voltage from a PC USB port is not that clean to begin with,so the cable just adds inductance, which adds noise. This is the reason why heavier power and ground wires improve things.. The best scenerio of course is to use an external high quality supply and not the one from the computer.

Improving the common-mode noise will also reduce jitter.. There are two ways to accomplish this:

Add a CM filter to the cable
Get a USB interface withgalvanic isolation

Better Sheilding of the cable can also have an effect, but I’m not sure why.  There may be RFI to the receiver or impact on the impedance.

Steve N.
Empirical Audio

audioengr
3,282 posts
 
Good cable, but TotalDAC cable beats AQ Diamond.
More to discover